Microscopy system and method

ABSTRACT

A microscopy system method for inspecting a retina of an eye including generating an inverted intermediate image of the retina using an ophthalmoscopic lens; detecting a left image of the intermediate image from a left viewing direction and detecting a right image of the intermediate image from a right viewing direction; and displaying an inverted representation of the detected left image to a right eye of a user and displaying an inverted representation of the detected right image to a left eye of the user.

This application claims the benefit of priority application DE 103 36475.7 filed in Germany on Aug. 8, 2003. The subject matter of thisapplication is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a microscopy system and method. In particular,the invention relates to a surgical microscopy system of the binoculartype and a microscopy method for inspecting a retina of an eye.

2. Brief Description of Related Art

From U.S. Pat. No. 4,786,154 there is known a stereo-microscopy systemcomprising an objective lens for transforming an object-side imagingbeam emerging from an object plane of the objective lens into animage-side imaging beam. A left zoom system and a right zoom system aredisposed within the image-side imaging beam. The left zoom system picksup a left beam portion of the image-side imaging beam and supplies thatportion with an adjustable magnification to a left ocular of themicroscopy system. Similarly, the right zoom system picks up a rightbeam portion of the image-side imaging beam and supplies that portionwith an adjustable magnification to a right ocular of the microscopysystem. Two semitransparent mirrors are disposed in each of the left andright beam portions in-between of the respective zoom system and ocular.A first of the two mirrors is used to supply light of the respectivebeam portion to a camera. Images detected by the camera are supplied toa controller for further processing. The controller supplies theprocessed images to a display, and light generated by the display issuperimposed with the respective beam portion by the secondsemitransparent mirror. When looking into the oculars, the user mayperceive a direct image of the object and a superimposed representationgenerated by the displays.

The two semitransparent mirrors disposed in the beam paths tend toincrease the volume and length of the microscopy system.

From EP 1 191 381 A2 there is known a stereo-microscopy system which isconfigured to be used for surgery at the human eye and to generate astereo-microscopic image of a retina of the eye. For this purpose, anophthalmoscopic lens is inserted in a beam path between the objectivelens of the microscopy system and the eye under surgery. Theophthalmoscopic lens generates an intermediate image of the retina ofthe eye in the object plane of the objective lens. The intermediateimage is an inverted image, and the microscopy system comprises opticsfor interchanging the stereo channels of the microscopy system and forinverting each of the stereo-images supplied to oculars of themicroscopy system.

Such optics also tends to increase the volume and length of themicroscopy system.

SUMMARY OF THE INVENTION

The present invention has been accomplished taking the above problemsinto consideration.

It is an object of the present invention to provide a stereo-microscopysystem of a simplified configuration and which is suitable to be used incombination with an ophthalmoscopic lens.

It is a further object of the present invention to provide an improvedmicroscopy method for inspecting a retina of an eye.

The foregoing objects are accomplished by providing a microscopy systemfor generating a magnified stereoscopic image of an object. Themicroscopy system comprises an objective lens for transforming anobject-side beam emerging from an object plane of the objective lensinto an image-side beam. Left and right cameras are disposed within theimage-side beam to be supplied with light of left and right beamportions of the image-side beam for detecting an image of the objectfrom left and right viewing directions, respectively. The microscopysystem further comprises left and right displays for generatingrepresentations of the object to be viewed by a left and right eyes,respectively, of a user.

A control system of the microscopy system has first and second modes ofoperation. In the first mode of operation, the controller supplies aninverted representation of the image detected by the left camera to theright display, and supplies an inverted representation of the imagedetected by the right camera to the left display.

The invention thus provides a simplified microscopy system to be used incombination with an ophthalmoscopic lens and which performs thenecessary interchanging of the stereo-channels together with thenecessary image inversion. Other than in the conventional system, wherethe interchanging of the stereo-channels and image inversion is achievedby using complicated optical means, the interchanging of thestereo-channels and image inversion is achieved in the microscopy systemaccording to the present invention by electronic means provided by thecontroller.

In the second mode of operation, a non-inverted representation of theimage detected by the left camera is supplied to the left display, and anon-inverted representation of the image detected by the right camera issupplied to the right display. In the second mode of operation themicroscopy system may be used for inspecting an object which is disposedin the object plane of the objective lens. The microscopy system may beswitched from the first mode of operation to the second mode ofoperation, i.e. from an operation involving use of an ophthlamoscopiclens to an operation without involving such ophthalmoscopic lens, by aswitching of the control system and without making it necessary to moveoptical components into the beam path or out of the beam path.

According to an exemplary embodiment of the invention, the left andright displays are comprised in a head mounted display. The user maythen freely move relative to the objective lens while viewing themagnified stereoscopic representation of the object. According to afurther exemplary embodiment, the left and right displays are mounted ona support such that the user has the choice of viewing the magnifiedrepresentation of the object through the displays or viewing directlyonto the object or some other point of interest.

According to some embodiments of the invention, the microscopy systemfurther comprises a left ocular and a right ocular which are suppliedwith light of the left and right beam portions such that the user mayalso perceive a purely optical stereomicroscopic representation of theobject by looking into the oculars. In such embodiments, the microscopysystem preferably comprises a beam splitter for supplying light of theleft and right beam portions to both the respective ocular and therespective camera.

In an exemplary embodiment herein, the inspection, in the second mode ofoperation for inspecting the object disposed in the object plane withoutan ophthalmoscopic lens disposed in the beam path, is performed usingthe optical beam path between the objective lens and the oculars. In thefirst mode of operation for inspecting the object using the invertingophthalmoscopic lens, the inspection is performed using therepresentations generated by the displays and superimposed with a beampath towards the oculars, wherein inverted representations of the imagesdetected by the cameras are supplied while interchanging thestereo-channels.

In a further exemplary embodiment herein, the microscopy systemcomprises a beam switch having a first switching state in which thesupply of the beam portions to the oculars is allowed, and a secondswitching state in which the supply of the beam portions to the ocularsis blocked.

According to an exemplary embodiment of the invention, the operation ofthe beam splitter is synchronized with a switchable illumination systemof the microscopy system, wherein the illumination system has a firstillumination state in which an illuminating beam is directed towards theinspected object, and a second illumination state in which anilluminating beam is not directed onto the object. In the first mode ofoperation of the control system the beam path between the objective lensand the oculars is not blocked, wherein the object is not illuminated inthis first mode of operation, however. Thus the user will not perceivethe object through the optical beam path when looking into the ocularsin the first mode of operation. He will then perceive the representationgenerated by the displays, which generate inverted representations ofthe object while interchanging the stereo-channels. Thus, the user willperceive non-inverted representations of the object with a correctstereo base while using the ophthalmoscopic lens. The two beam portionsare permanently supplied to the cameras. The images of the object aresubstantially only detected in the second mode of operation of thecontrol system since it is only then that the illumination systemilluminates the object with the illuminating beam. In this second modeof operation the direct beam path of the two beam portions towards theoculars is blocked such that the user will not perceive the directoptical inverted image with interchanged stereo-channels when lookinginto the oculars in the second mode of operation. If necessary, thecamera, the display or the corresponding controller may comprise amemory for storing the images detected by the cameras during the secondmode of operation where the cameras will detect the images.Representations of the stored images will be supplied to the displaysduring that time where the illuminating beam is not incident on theobject. Such memory may not be necessary if a response time of thedisplay is sufficiently low such that the intensity variations caused bythe intermittent illumination of the object are not perceived by theuser.

Preferably, the switching between the first and second modes ofoperation is periodically performed at a sufficiently high frequencysuch that the user will substantially continuously perceive the invertedrepresentations with interchanged stereo-channels of the object.

The invention further provides a microscopy method for inspecting aretina of an eye, the method comprising: generating an invertedintermediate image of the retina; detecting a left image of theintermediate image from a left viewing direction and detecting a rightimage of the intermediate image from a right viewing direction; anddisplaying an inverted representation of the detected left image to aright eye of a user and displaying an inverted representation of thedetected right image to a left eye of the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The forgoing as well as other advantageous features of the inventionwill be more apparent from the following detailed description ofexemplary embodiments of the invention with reference to theaccompanying drawings, wherein:

FIG. 1 schematically shows a stereo-microscopy system which may be usedin combination with an ophthalmoscopic lens, according to a firstembodiment of the invention;

FIG. 2 schematically shows a stereo-microscopy system which may be usedin combination with an ophthalmoscopic lens, according to a secondembodiment of the invention; and

FIG. 3 schematically shows a stereo-microscopy system which may be usedin combination with an ophthalmoscopic lens, according to a thirdembodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the exemplary embodiments described below, components that are alikein function and structure are designated as far as possible by alikereference numerals. Therefore, to understand the features of theindividual components of a specific embodiment, the descriptions ofother embodiments and of the summary of the invention should be referredto.

FIG. 1 schematically illustrates a microscopy system 1 comprising anobjective lens system 3 having plural objective lenses 5 fortransforming an object-side imaging beam 9 emerging from an object plane7 of the objective lens 3 into an image-side imaging beam 11.

A beam splitter arrangement 13 is disposed in the image-side imagingbeam 11. The beam splitting arrangement 13 comprises a prism 15 of theBauernfeind type and having a wedge shaped prism 17 cemented thereon. Asplitting of the beam path is generated at an interface 19 of the beamsplitting arrangement, wherein a beam path for a main user straightlytraverses the interface 19. A pair of zoom system 21 each having pluralzoom lenses 23 is disposed in the beam path of the main user downstreamof the beam splitter arrangement. Only one of the two zoom systems 21 isvisible in FIG. 1 while hiding the other zoom system.

Each of the zoom systems picks up a beam portion 25 of the image-sideimaging beam 11 to supply that beam portion 25 to a beam splittingarrangement 27. The beam splitting arrangement 27 comprises a prism 29of the Bauernfeind type having a first surface 31 facing towards thezoom system 21, wherein the beam portion 25 supplied by zoom system 21enters prism 29 through the first surface 31. The prism 29 has a secondsemitransparent surface 33 for splitting the beam path into an ocularbeam path 35 and a camera beam path 37, wherein the camera beam pathstraightly traverses the semitransparent surface 33 and the ocular beampath 35 is reflected from second surface 33. The ocular beam path 35 isthen reflected from the first surface 31 of prism 29 by internal totalreflection and then emerges from prism 29 by traversing a third surface39 of prism 29 to enter a body of a tube 41 comprising plural lenses 43and a beam deflector 45 to supply the ocular beam path to oculars 47.The oculars 47 are pivotable to be adaptable to a distance of the eyesof the user.

The camera beam path 37 traverses the second surface 33 of prism 29 andenters a prism 48 which is joined to prism 29 by cementing. The camerabeam path 37 straightly traverses prism 48 and emerges therefrom througha surface 49 to be incident into a camera 51 having a camera adapteroptics 53 and a CCD chip 55. Images detected by the CCD chip 55 are readout by a controller 57 to be stored in an archive 59, such as a magnetictape or other, or to be displayed on a computer display 61 afterperforming some image processing, if desired. The controller 57 isfurther configured to supply data to a display 65. The data may comprisethe images detected by camera 51, the corresponding image processedimages or other data such as data entered by using a keyboard 63. Thedisplay 65 comprises a LCD chip 67 and a display optics 69. Lightgenerated by the display 65 enters prism 48 by traversing a surface 71thereof under such an angle that a beam path 73 of the display issuperimposed with the ocular beam path 35 after traversing the secondsurface 33 of prism 29. When looking into the oculars 47 the user willperceive both the optical image of the object plane 7 supplied by theobject-side imaging beam 11 and the corresponding beam portions 25, andthe superimposed representations generated by the displays 65.

A beam path 81 reflected by prism 15 of the Bauernfeind type is suppliedto oculars 83 for an assistant user to perceive an optical image ofobject plane 7. A pair of zoom systems 84 and a tube 85 having a similarconfiguration as zoom system 21 and tube 41 illustrated above aredisposed in beam path 81.

FIG. 2 schematically illustrates a microscopy system 1 a comprising anobjective lens 3 a having an object plane 7 a. The objective lens 3 atransforms an object-side imaging beam 9 a emerging from an object plane7 a into an image-side imaging beam 11 a. Two cameras 41 al and 41 arare disposed in the image-side imaging beam 11 a (the additionalcharacter l stands for “left”, and the additional character r stands for“right”). The cameras 51 al and 51 ar each comprise a camera adapteroptics 53 al,r and a CCD chip 55 al,r and detect images of the objectplane 7 a from left and right viewing directions, respectively. In theembodiment shown in FIG. 2 zoom systems are not disposed in the beampath between the objective lens and the cameras; corresponding zoomsystems may be provided, however, for optically changing a magnificationof the images detected by cameras 51 al,r.

The microscopy system la is used for inspecting a retina 91 of an eye 93and comprises an opththalmoscopic lens 94 generating an intermediateimage of retina 91 in the object plane 7 a. An example of anophthalmoscopic lens is disclosed in U.S. Pat. No. 4,728,183. The imagesdetected by cameras 51 al, 51 ar are inverted pseudo-stereoscopicimages. This means that the stereo-channels are interchanged and thatthe left and right and up and down sides of the images are inverted.

The images detected by cameras 51 al, 51 ar are supplied to controller57 a via data lines 101 l, 101 r, respectively, transformed byelectronic image inverters 103 to have a correct orientation, andsupplied to a head mounted display 105. The head mounted displaycomprises a left display 65 l to be viewed with a left eye of the user,and a right display 65 r to be viewed by a right eye of the user. Theimages detected by camera 51 al are supplied to display 65 r after imageinversion, and the images detected by camera 51 ar are supplied todisplay 65 l after image inversion, such that the user will perceive acorrectly oriented representation of the retina 91 with a correct stereoimpression.

If the user intends to inspect an object disposed in the object plane 7a without using the ophthalmoscopic lens 94, he will switch thecontroller 57 a to a second mode of operation, wherein a correspondingswitch 109 is only schematically indicated in FIG. 2. In the second modeof operation the images detected by camera 51 al are supplied to display65 l without being inverted, and the images detected by camera 51 a aresupplied to display 65 r without being inverted.

FIG. 3 shows a stereo-microscopy system 1 b which can be operated in afirst mode of operation for inspecting a retina using an ophthalmoscopiclens and a second mode of operation for inspecting an object withoutsuch ophthalmoscopic lens.

The inspection without ophthalmoscopic lens is a direct opticalinspection wherein an object-side beam 9 b is transformed into animage-side beam 11 b by an objective lens 3 b. A pair of zoom systemspicks out a pair of beam portions 25 b which are finally supplied torespective oculars 47 b. Only one zoom system 21 bl is shown in FIG. 3.The two beam portions 25 b are split by a prism 29 b of the Bauernfeindtype. A first portion of the split beams forms an ocular beam path 35 band is supplied to the oculars 47 b via a tube arrangement 41 b. Asecond portion of the split beams forms a camera beam path 37 b and issupplied to a pair of cameras 51 b having a COD chip 55 b, wherein acamera 51 bl detects an image of an object plane from a left viewingdirection, and a second camera (not shown in FIG. 3) detects an image ofthe object plane from a right viewing direction.

The images detected by cameras 51 b are read out by a controller 57 band supplied to displays 65 b having LCD chips 67 b for displaying theimages.

In the first mode of operation where the ophthalmoscopic lens is usedfor inspection, the images of the displays 65 b are superimposed withthe ocular beam paths by a hinged mirror 111 which is disposed in theocular beam paths 53 b as indicated by solid lines in FIG. 3 b. In thisshown position the hinged mirror 111 blocks the light emerging from theobject and supplied by the zoom systems 21 b towards the oculars. Whenlooking into the oculars 47 b the user will perceive the images of therepresentations generated by the displays 65 b wherein the controller 57b has inverted the images detected by cameras 51 b and has interchangedthe stereo-channels. Thus, the user will perceive an image of a retinathrough an ophthalmoscopic lens (not shown in FIG. 3) with a correctorientation and correct stereoscopic impression.

For inspecting the object without ophthalmoscopic lens, the hingedmirror 111 is rotated by a corresponding actuator (not shown in FIG. 3)under the control of controller 57 b to a position shown in broken linesin FIG. 3. In such position the mirror 111 does not superimpose thelight generated by the displays 65 b with the ocular beam path, and themirror 111 does not block the light emerging from the object andsupplied to the oculars 47 b through the objective lens 3 b, the zoomsystems 21 b and the beam splitter 29 b. The user may directly inspectthe object by pure optical imaging, accordingly.

Also the microscopy system 1 is configured for an inspection involvingan ophthalmoscopic lens. For this purpose, the microscopy system 1comprises an illumination system 121 comprising a light source 123 and areflector 125 for generating a light beam 127. A collimator 129 isprovided for forming light beam 127 to be a collimated beam 131. Afurther lens group 133 is provided to transform collimated beam 131 intoan illuminating beam 135 suitable for illuminating an object field inobject plane 7. The illumination system 121 is schematically illustratedin FIG. 1 such that the illuminating beam 135 is obliquely incident onobject plane 7. Other embodiments suitable for ophthalmoscopic surgerywill use illuminating beams reflected from deflecting mirrors such thatthe beam is incident onto the object plane under only a small anglerelative to the optical axis of the objective lens.

The illuminating system 121 further comprises a chopper 137 having amotor 139 and a chopper wheel 149 having plural chopper blades foralternatingly blocking the illuminating beam 135 and allowing the beamto pass through. A rotating speed and phase of the motor 139 iscontrolled by controller 57. The object will alternatingly beilluminated and not be illuminated. A beam shutter 141 is disposed in abeam path between the prism 29 of the Bauernfeind type and the tube 41.In a state of the illuminating system 121 where the object isilluminated, the controller switches the light shutter 141 into itslight blocking state such that the user will not perceive the opticalimage of the object when looking into the oculars 47. The cameras 51will detect an image of the object in such illumination state and thecontroller 57 will read out those images, invert the images as indicatedby inverters 103 in FIG. 2 and supply the inverted images to displays 65which will display the corresponding images also during those timeintervals in which the chopper wheel 149 blocks the illuminating beam135. At that time, the controller 57 controls the light shutter 141 tobe switched into its light transmitting state such that therepresentations of the object generated by displays 65 have a correctorientation and will be perceived with a correct stereoscopicimpression.

Summarized, a microscopy system method for inspecting a retina of an eyecomprises generating an inverted intermediate image of the retina usingan ophthalmoscopic lens; detecting a left image of the intermediateimage from a left viewing direction and detecting a right image of theintermediate image from a right viewing direction; and displaying aninverted representation of the detected left image to a right eye of auser and displaying an inverted representation of the detected rightimage to a left eye of the user.

The present invention has been described by way of exemplary embodimentsto which it is not limited. Variations and modifications will occur tothose skilled in the art without departing from the scope of the presentinvention as recited in the appended claims and equivalents thereof.

1. A microscopy system for generating a magnified stereoscopicrepresentation of an object, the system comprising: an objective lensfor transforming an object-side imaging beam emerging from an objectplane of the objective lens into an image-side imaging beam; anophthalmoscopic lens which is selectively disposable in a beam pathbetween the object and the object plane of the objective lens togenerate an inverted image of the object in a region of the objectplane; a left camera configured to be supplied with light of a left beamportion of the image-side imaging beam, for detecting an image of theobject from a left viewing direction; a right camera configured to besupplied with light of a right beam portion of the image-side imagingbeam, for detecting an image of the object from a right viewingdirection; a left display for generating a representation of the objectto be supplied to a left eye of a user; a right display for generating arepresentation of the object to be supplied to a right eye of the user;and a controller configured to be operated in a first mode of operationto receive the image detected by the left camera and to supply aninverted representation of the image detected by the left camera to theright display, and to receive the image detected by the right camera andto supply an inverted representation of the image detected by the rightcamera to the left display, wherein the controller is further configuredto operate in a second mode of operation to receive the image detectedby the left camera and to supply a non-inverted representation of theimage detected by the left camera to the left display, and to receivethe image detected by the right camera and to supply a non-invertedrepresentation of the image detected by the right camera to the rightdisplay, wherein the ophthalmoscopic lens is removable from the beampath between the object and the object plane of the objective lens,wherein in the first mode of operation, the ophthalmoscopic lens isdisposed in the beam path between the object and the object plane of theobjective lens, and in the second mode of operation, the ophthalmoscopiclens is not disposed in the beam path between the object and the objectplane of the objective lens, a left ocular, a right ocular, and at leastone optical component configured to provide a beam path for supplyinglight of the left beam portion to the left ocular and supplying light ofthe right beam portion to the right ocular, a beam splitter forsplitting the light of the left beam portion for supply to both the leftocular and the left camera, and for splitting the light of the rightbeam portion for supply to both the right ocular and the right camera, abeam switch configured to have a first switching state in which thelight of the left beam portion is blocked and not supplied to the leftocular and in which the representation generated by the left camera issupplied to the left ocular, and in which the light of the right beamportion is blocked and not supplied to the right ocular and in which therepresentation generated by the right camera is supplied to the rightocular, and wherein the beam switch is configured to have a secondswitching state in which the light of the left beam portion is suppliedto the left ocular, and the light of the right beam portion is suppliedto the right ocular, wherein the controller is configured to switch thebeam switch into the first switching state in the first mode ofoperation, and to switch the beam switch into the second switching statein the second mode of operation.
 2. The microscopy system according toclaim 1, wherein the left display and the right display are provided ina head mounted display.
 3. The microscopy system of claim 1, whereinsaid controller further comprises: at least one electronic imageinverter for transforming images detected by at least one of said leftcamera and said right camera.
 4. A microscopy system for generating amagnified stereoscopic representation of an object, the systemcomprising: an objective lens for transforming an object-side imagingbeam emerging from an object plane of the objective lens into animage-side imaging beam; an ophthalmoscopic lens which is selectivelydisposable in a beam path between the object and the object plane of theobjective lens to generate an inverted image of the object in a regionof the object plane; a left camera configured to be supplied with lightof a left beam portion of the image-side imaging beam, for detecting animage of the object from a left viewing direction; a right cameraconfigured to be supplied with light of a right beam portion of theimage-side imaging beam, for detecting an image of the object from aright viewing direction; a left display for generating a representationof the object to be supplied to a left eye of a user; a right displayfor generating a representation of the object to be supplied to a righteye of the user; and a controller configured to be operated in a firstmode of operation to receive the image detected by the left camera andto supply an inverted representation of the image detected by the leftcamera to the right display, and to receive the image detected by theright camera and to supply an inverted representation of the imagedetected by the right camera to the left display, wherein the controlleris further configured to operate in a second mode of operation toreceive the image detected by the left camera and to supply anon-inverted representation of the image detected by the left camera tothe left display, and to receive the image detected by the right cameraand to supply a non-inverted representation of the image detected by theright camera to the right display, wherein the ophthalmoscopic lens isremovable from the beam path between the object and the object plane ofthe objective lens, wherein in the first mode of operation, theophthalmoscopic lens is disposed in the beam path between the object andthe object plane of the objective lens, and in the second mode ofoperation, the ophthalmoscopic lens is not disposed in the beam pathbetween the object and the object plane of the objective lens, a leftocular, a right ocular, and at least one optical component configured toprovide a beam path for supplying light of the left beam portion to theleft ocular and supplying light of the right beam portion to the rightocular, a switchable illumination system configured to have a firstilluminating state in which an illuminating beam is directed onto theobject, and a second illuminating state in which the illuminating beamis not directed onto the object, a beam switch configured to have afirst switching state in which the light of the left beam portion isblocked and not supplied to the left ocular and in which therepresentation generated by the left camera is supplied to the leftocular, and in which the light of the right beam portion is blocked andnot supplied to the right ocular and in which the representationgenerated by the right camera is supplied to the right ocular, andwherein the beam switch is configured to have a second switching statein which the light of the left beam portion is supplied to the leftocular, and the light of the right beam portion is supplied to the rightocular, wherein the controller is configured to switch the beam switchinto the first switching state and to switch the illumination systeminto the first illuminating state in the first mode of operation, and toswitch the beam switch into the second switching state and to switch theillumination system into the second illuminating state in the secondmode of operation.
 5. The microscopy system of claim 4, wherein saidcontroller further comprises: at least one electronic image inverter fortransforming images detected by at least one of said left camera andsaid right camera.
 6. The microscopy system according to claim 4,wherein the left display and the right display are provided in a headmounted display.